FIGURE 5.

Santamarine induces ROS and regulates the cellular stress response. (A) The intracellular ROS accumulation was determined by DCFH-DA staining. (B) The intracellular superoxide anion accumulation was determined by DHE staining. After treating HeLa cells with vehicle (control) or santamarine at indicated concentrations for 6 h, they were stained with DCFH-DA (10 μM) and DHE (10 μM) for 30 min, respectively, and analyzed by fluorescence microscope to obtain phase contrast (top) and fluorescence (bottom) images. The images represent three independent experiments performed in triplicate. Scale bar = 20 μm. (C) The intracellular total thiol homeostasis responded to an increasing concentration of santamarine treatment. (D) The intracellular total thiol homeostasis responded to different times of a fixed concentration of santamarine treatment. After the increasing concentrations of santamarine (10, 20, or 40 μM) were exposed to treat HeLa cells for 24 h, or 50 μM of santamarine was exposed to treat HeLa cells for an indicated time (6, 12, or 24 h), the total thiol level in cell lysis was used DTNB titration determination. All data were from three independent experiments in triplicate. **p < 0.01 vs. the control group in (C), the 24 h group in (D).